Antioxidant Activity Of Quercetin Research Articles

Simultaneous ingestion of apple pectin enhances the absorption and antioxidant activity of quercetin in rats

Simultaneous ingestion of apple pectin enhances the absorption and antioxidant activity of quercetin in rats

In vitro antioxidant activity, antidiabetic activity and in silico docking studies of 3,3′,4′,5,7-pentahydroxyflavone and stigmasta-5,22-dien-3β-ol isolated from aerial parts of Euphorbia milii. Des moul

This research focused on evaluating the in vitro antioxidant, antidiabetic activities and Insilco docking properties of two phytocompounds 3,3′,4′,5,7-Pentahydroxyflavone (Quercetin) and Stigmasta-5,22-dien-3β-ol (Stigma sterol). These compounds were isolated from the methanol extract of stem and ethanol extract of flower of the E. milii plant. The antioxidant properties of these phytocompounds were studied using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. A comparison was made between the antioxidant activity of quercetin, stigma sterol, and the standard drug ascorbic acid. The results indicated that quercetin showed significant antioxidant activity, suggesting its potential as an effective antioxidant. Additionally, in vitro antidiabetic activity was investigated through α-amylase and α-glucosidase inhibition assays. Screened compounds exhibited significant % of inhibition values against two carbohydrate hydrolysing enzymes, α-amylase and α-glucosidase compared to reference drug (acarbose). Furthermore, molecular docking studies were conducted to analyse the interaction of the compounds with α-d-glucose (PDB ID: 3A4A) and PTP1B I (PDB ID: 1T49) as target molecules. These docking studies provided further insights to support the biological findings of the compounds isolated from E. milii aerial parts.

Compound Characterization and Evaluation of Antioxidant Potential of Ethanol Extract Spatholobus littoralis Hassk in Kolaka, Southeast Sulawesi, Indonesia

The bajakah tampala plant (Spahtolobus littoralis Hassk) has been traditionally believed by the public to cure cancer, tumors, heart disease, stroke, and diabetes. However, empirically the public does not yet know the chemical compound content and there have been no studies on biological activity tests, especially the antioxidants of bajakah tampala from Kolaka, Southeast Sulawesi. The aim of this research is a qualitative analysis of the chemical compounds of the ethanol extract of bajakah tampala roots and testing of antioxidant activity. Analysis of the chemical compounds of the ethanol extract of bajakah tampala roots using an FT-IR spectrophotometer and LC-MS/MS. The antioxidant activity of the bajakah tampala root ethanol extract was tested using the DPPH immersion method and the absorption was measured using a UV-Viss spectrophotometer and using the positive control quercetin. The results of the research showed that the ethanol extract of bajakah tampala roots had 8 chemical components that were detected, namely compound 1 apocynoside I, compound 2 quercetin, compound 3 hexosylphingosine, compound 4 3-hydroxy-7-methoxybaicalein, compound 5 momor-cerebroside I, compound 6 ambronal, compound 7 stigmastan-3,6-dione, and compound 8 trilaurin. The ethanol extract of bajakah tampala roots has an antioxidant activity of 21.75 µg/mL which is lower, compared to the antioxidant activity of quercetin of 2.91 µg/mL as a positive control, however the antioxidant activity of the ethanol extract of bajakah tampala roots is still included in the very strong category.

Fabrication of polyphenol nanoparticles co-stabilized with different polyvinylpyrrolidone concentrations: Effects on particle stability, drug release and cellular uptake

Curcumin (CUR) and quercetin (QUE) possess low stability owing to their limited solubility in physiological conditions, and hence low bioavailability. This study evaluated polyvinylpyrrolidone (PVP) as a co-stabilizer and coating material to overcome the abovementioned limitations as well as improve the physical stability of fabricated CUR and QUE nanoparticle (NP). CUR and QUE were encapsulated into a pluronic based nanocarrier and co-stabilized with different PVP concentrations (0.1–0.7% w/v). The nanoparticles co-stabilized in different PVP concentrations followed the anomalous Non-Fickian involving both diffusion and swelling controlled transport release behaviors. The fabricated nanoparticles were evaluated for its stability in different pH conditions (pH 5.6 and 7.4 which mimics tumor microenvironment and physiological condition). The particle sizes, polydispersity index and drug contents did not undergo significant changes at different pH conditions. The effect of storage stability (25 °C/60% RH and 40 °C/75% RH) on CUR and QUE anti-oxidant activity and cellular internalization were also measured at different predetermined time points (up to 3 months). Higher PVP concentration enhanced cellular uptake and permeability into Calu-3 cells as well as stabilized the NP with minimal loss of drug content up to 3 months of storage. As a conclusion, higher PVP concentration as a co-stabilizer was needed to improve the stability of CUR-QUE-NPs for a prolonged period of storage and subsequently retained their antioxidant activities.

Advance in the pharmacological effects of quercetin in modulating oxidative stress and inflammation related disorders.

Numerous pharmacological effects of quercetin have been illustrated, including antiinflammation, antioxidation, and anticancer properties. In recent years, the antioxidant activity of quercetin has been extensively reported, in particular, its impacts on glutathione, enzyme activity, signaling transduction pathways, and reactive oxygen species (ROS). Quercetin has also been demonstrated to exert a striking antiinflammatory effect mainly by inhibiting the production of cytokines, reducing the expression of cyclooxygenase and lipoxygenase, and preserving the integrity of mast cells. By regulating oxidative stress and inflammation, which are regarded as two critical processes involved in the defense and regular physiological operation of biological systems, quercetin has been validated to be effective in treating a variety of disorders. Symptoms of these reactions have been linked to degenerative processes and metabolic disorders, including metabolic syndrome, cardiovascular, neurodegeneration, cancer, and nonalcoholic fatty liver disease. Despite that evidence demonstrates that antioxidants are employed to prevent excessive oxidative and inflammatory processes, there are still concerns regarding the expense, accessibility, and side effects of agents. Notably, natural products, especially those derived from plants, are widely accessible, affordable, and generally safe. In this review, the antioxidant and antiinflammatory abilities of the active ingredient quercetin and its application in oxidative stress-related disorders have been outlined in detail.

Enhancement of antioxidant activities and stabilities of quercetin and isoquercetin through the combination of nanoencapsulation and hydrogel incorporation

This study investigated the possibility of improving the antioxidant activities and solubilities of quercetin (QUE) and isoquercetin (IQUE) through a combination of nanoencapsulation with gel incorporation. QUE- and IQUE-loaded nanoparticles (QUE and IQUE NPs, respectively) were prepared through ionic gelation between chitooligosaccharide and poly-γ-glutamic acid. The antioxidant activities of QUE and IQUE increased by 2.5 and 3.5 times, respectively, after nanoencapsulation. Furthermore, QUE and IQUE NP-filled gelatin gels (G-QUE and G-IQUE NPs, respectively) showed higher antioxidant stabilities than QUE and IQUE NPs, respectively. G-QUE and G-IQUE NPs exhibited significantly (p < 0.05) higher G’ values than free QUE and IQUE in gels, respectively. Moreover, the hardness of G-QUE NPs was significantly (p < 0.05) higher than that of free QUE in gel. In conclusion, combining nanoencapsulation and gel incorporation can improve the antioxidant activities, stabilities, and physical properties of QUE and IQUE.

Encapsulation of quercetin into zein-ethyl cellulose coaxial nanofibers: Preparation, characterization and its anticancer activity

In order to efficiently improve the colon-targeted delivery of quercetin, the hydrophobic core-shell nanofibers were fabricated to encapsulate quercetin using ethyl cellulose as the shell and zein as the core by coaxial electrospinning. The encapsulation efficiency of coaxial nanofibers reached >97 %. FTIR and XRD results revealed the interactions between quercetin and wall materials and quercetin was encapsulated in an amorphous state. The thermal stability and surface hydrophobicity of coaxial nanofibers were improved compared to the uniaxial zein fibers. After in vitro gastrointestinal digestion, the quercetin release from core-shell nanofibers was <12.38 %, while the corresponding value for zein fibers was 36.24 %. DPPH and FRAP assays showed that there was no significant difference in the antioxidant activity of quercetin before and after encapsulation. Furthermore, the encapsulated quercetin exhibited similar anti-proliferative activity against HCT-116 cells compared to the free form. The results suggest these coaxial nanofibers have potential applications in functional foods.

Oxidized quercetin has stronger anti-amyloid activity and anti-aging effect than native form

Quercetin (QUE) is one of the most widely distributed and used flavonoid. It has many biological activities and pharmacological effect. As a polyhydroxy phenol, QUE is easily oxidized. However, it is unclear how its biology efficacy changes after oxidation. In this study, we prepared QUE oxidation product (QUE-ox) through enzymatic oxidation of QUE. We found the oxidation reduced the antioxidant activity of QUE but increased its anti-amyloid activity in vitro. In C. elegans, oxidation increased the anti-aging effects of QUE. Further experiments showed that both QUE and QUE-ox delayed aging by improving stress resistance, but they have different molecular mechanisms. QUE mainly increased the transcriptional activities of DAF-16 and SKN-1, resulting in the enhancement of expression of oxidative stress resistance genes, and further increased the oxidative resistance in C. elegans. QUE-ox increased the transcriptional activities of DAF-16 and HSF-1 transcription factors to enhance the heat stress resistance. In summary, our study indicated oxidized QUE has stronger anti-amyloid activity and anti-aging effect than native form. This study provides a theoretical basis for the safe and rational application of QUE, especially for its antioxidant, anti-amyloid and anti-aging effects.

Inhalation exposure to crude oil vapor induces behavioural deficits by increasing oxidative stress and histopathological changes in rat hippocampus: Quercetin therapeutic approach

ObjectiveInhalation exposure to crude oil vapor (COV) and petroleum products is considered responsible for neurobehavioral toxicity in human and animal models. The antioxidant activity of quercetin (Que) and its derivatives are promising for protecting the hippocampus. This study aimed to evaluate the neuroprotective role of Que against COV-induced behavioral alterations and hippocampus damage. MethodsEighteen adult male Wistar rats were randomly divided into the following three groups (n = 6): the control, the COV, and the COV + Que group. The inhalation method was used to expose the rats to crude oil vapors for 5 h daily, and Que (50 mg/kg) was administered orally. After 30 days of treatment, the spatial working memory and anxiety levels were evaluated using the cross-arm maze and elevated plus maze (EPM), respectively. TUNEL assay and hematoxylin-eosin (H&E) staining were used to identify the necrosis, normal and apoptotic cells in the hippocampus. Moreover, the levels of oxidative stress biomarkers including malondialdehyde (MDA), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (TAC) were investigated in the hippocampus tissue. ResultsThe results indicated that exposure to COV was associated with a significant decrease in spatial working memory and activity of CAT, TAC, SOD, and GPx enzymes compared to the control (P < 0.05). Moreover, COV significantly increased the level of anxiety, MDA, and hippocampal apoptosis (P < 0.05). The simultaneous administration of quercetin along with exposure to COV improved the behavioral alterations, activity of antioxidant enzymes, and hippocampal apoptosis. ConclusionsThese findings suggest that quercetin prevents COV-induced hippocampal damage by enhancing the antioxidant system and preventing cell apoptosis.

Quercetin as an effective antioxidant against superoxide radical

Background: Quercetin is considered one of the most studied flavonols widely found in fruits and vegetables. Food preparation and storage affect the level of quercetin in food, as these processes can cause a partial or complete reduction in flavonol levels. Quercetin, as a bioactive compound, has beneficial effects on the human body and with various diseases due to its potent antioxidant properties. Quercetin is a scavenger of free radicals and exerts its effects in various body fluids (e.g., saliva, synovial fluid, blood). Because of this, it is essential to know the effect of pH on its antioxidant properties.Objective: This study aims to determine the antioxidant capacity of quercetin against superoxide radicals depending on pH using a spectroscopic method.Methods: The antioxidant properties of quercetin in the concentration range from 5 to 50 μg/ml against superoxide radicals were measured at pH values of 6.5 to 8. Superoxide radicals were generated in the photooxidation reaction of methionine with riboflavin. Inhibition of superoxide radicals by quercetin was detected spectrophotometrically in reaction with NTB.Results: Quercetin is an effective superoxide radical scavenger with the highest antioxidant capacity observed at a slightly acidic pH of 6.5. The antioxidant activity of quercetin increased with increasing concentration; effective antioxidant capacity of quercetin was in the experiment at a concentration above 30 µg/ml.Conclusion: Quercetin is a widely occurring flavonoid with many beneficial effects on the human body related to its antioxidant properties. Quercetin is an effective scavenger of superoxide radicals. Its correct dosage, processing, and storage, which significantly affect the antioxidant properties of quercetin, have a considerable impact on the effects of quercetin in the prevention and treatment of diseases. Since pH significantly affects biochemical processes in living organisms, our results could contribute to expanding information on the antioxidant properties of quercetin as a rich natural source of medicinal substances, depending on pH.Keywords:quercetin, antioxidant, superoxide radical, spectrophotometry

Synthesis, characterization, antioxidant activity of Quercetin, Rutin and Quercetin-Rutin incorporated β-cyclodextrin inclusion complexes and determination of their activity in NIH-3T3, MDA-MB-231 and A549 cell lines

Quercetin (Q) and rutin (R) are plant-originated polyphenolic flavonoids with considerably strong antioxidant and anticancer activity. Despite their potentials, low water solubility, stability problems and oral bioavailability limit their therapeutic use. The specific purpose of our study was to formulate inclusion complexes of Q and R with β-cyclodextrin (β-CD) to improve the solubility and also antioxidant activity of the flavonoids. Therefore 12 different complexes were prepared by both evaporation and lyophilization methods with 1:1 molar ratio in ethanol:water (1:1, v/v) solvent system. The characteristics of the complexes were also evaluated by yield%, zeta potential (ZP), entrapment efficiency (EE), 1H NMR, XRD, FT-IR, DSC analyses. In vitro dissolution studies were performed in comparison with pure substances. Antioxidant activity studies were carried out with DPPH tests. Cytotoxic evaluations of complexes were conducted with MTT tests on NIH 3T3, MDA-MB-231 and A549 cell lines. 1H- NMR analyses revealed the complex formation considering the shifts of the protons of the APIs as well as β-CD. ZP values were ranged between -21.20±0.56 mV and -7.10±0.62 mV. The aqueous solubility of Q and R were increased ∼29 fold and ∼35 fold, respectively. According to the MTT analyses results it has been shown that the flavonoids loaded complexes were particularly effective in MDA-MB-231 cells and 50% cell inhibition was observed even at 5 µM. The results of the analyses have demonstrated that the formation of inclusion complexes resulted in enhanced water solubility and cytotoxicity which will enhance their potential use in pharmaceutical applications.

Comparison of effects of quercetin and ascorbic acid on inflammatory cytokines and antioxidant biomarkers in infant rats using an experimental sepsis model.

There is ongoing research on treatments that promote antioxidant and anti-inflammatory mechanisms, which will reduce mortality in sepsis. In this study, we compared the anti-inflammatory and antioxidant activities of quercetin and ascorbic acid using a sepsis model induced in infant rats. A total of 28 infant rats 21-days-old that had just completed the lactation period were divided into four groups: control, sepsis, sepsis + quercetin, and sepsis + ascorbic acid. The sepsis model was created with an intraperitoneal injection of bacterial lipopolysaccharide. After 24 hours, blood samples were collected for analysis of serum levels of inflammatory cytokines (IL-1β, IL-6, TNF-α, and CRP) and antioxidants (CAT, GPx, SOD, and GST). The superoxide dismutase levels were significantly higher in the sepsis + ascorbic acid group compared to the sepsis and sepsis + quercetin groups. The levels of the most active cytokines in sepsis were significantly lower in the serum samples of the septic subjects who received quercetin and ascorbic acid. The antioxidant activity, which is impaired in sepsis, was increased by both molecules. We observed that these two molecules, which are free of side effects, have a positive influence on the progression of sepsis to severe and fatal sepsis in childhood (Tab. 2, Ref. 38).

Albumin-Based Zn (II)-Quercetin Enzyme Mimic Scavenging ROS for Protection against Cardiotoxicity Induced by Doxorubicin.

Doxorubicin (DOX) is a chemotherapeutic agent that can cause cardiotoxicity leading to progressive, chronic, life-threatening cardiomyopathy, called DOX-induced cardiomyopathy (DIC). DIC is a fatal cardiomyopathy with a worse prognosis compared to other cardiomyopathies and limits the use of DOX in malignancies due to its cardiotoxicity. DIC has been proven to be associated with reactive oxygen species (ROS)-induced side effect damage in cardiac myocytes. Currently, scavenging of reactive oxygen species is a practical strategy to reduce chemotherapy-associated DIC. Although quercetin has already been reported to have superior antioxidant activity, its clinical application is severely limited due to its rapid degradation and poor tissue absorption. Herein, we reported the preparation of a novel enzyme mimic via coordinated albumin, Zinc Ion (Zn2+) and quercetin. The enzyme mimics were capable of simultaneously increasing the biocompatibility and efficiently overcame the drawbacks of free quercetin, and were achieved by long circulation in vivo. Most importantly, these quercetin-based enzyme mimics had no effect on the antioxidant activity of quercetin. These beneficial therapeutic properties, together with high drug-carrying capacity and redox stimuli, will significantly improve quercetin's alleviation of chemotherapeutic cardiotoxicity without causing significant side effects. Therefore, nanoparticles of albumin-based Zn (II)-Quercetin have a promising clinical application as an effective agent for mitigating the cardiotoxicity of chemotherapy.

Antioxidant Activity of Quercetin in a H2O2-Induced Oxidative Stress Model in Red Blood Cells: Functional Role of Band 3 Protein.

During their lifespan, red blood cells (RBCs) are exposed to a large number of stressors and are therefore considered as a suitable model to investigate cell response to oxidative stress (OS). This study was conducted to evaluate the potential beneficial effects of the natural antioxidant quercetin (Q) on an OS model represented by human RBCs treated with H2O2. Markers of OS, including % hemolysis, reactive oxygen species (ROS) production, thiobarbituric acid reactive substances (TBARS) levels, oxidation of protein sulfhydryl groups, CD47 and B3p expression, methemoglobin formation (% MetHb), as well as the anion exchange capability through Band 3 protein (B3p) have been analyzed in RBCs treated for 1 h with 20 mM H2O2 with or without pre-treatment for 1 h with 10 μM Q, or in RBCs pre-treated with 20 mM H2O2 and then exposed to 10 µM Q. The results show that pre-treatment with Q is more effective than post-treatment to counteract OS in RBCs. In particular, pre-exposure to Q avoided morphological alterations (formation of acanthocytes), prevented H2O2-induced OS damage, and restored the abnormal distribution of B3p and CD47 expression. Moreover, H2O2 exposure was associated with a decreased rate constant of SO42− uptake via B3p, as well as an increased MetHb formation. Both alterations have been attenuated by pre-treatment with 10 μM Q. These results contribute (1) to elucidate OS-related events in human RBCs, (2) propose Q as natural antioxidant to counteract OS-related alterations, and (3) identify B3p as a possible target for the treatment and prevention of OS-related disease conditions or aging-related complications impacting on RBCs physiology.

Solid dispersions of quercetin-PEG matrices: Miscibility prediction, preparation and characterization

Quercetin is a bioflavonoid compound with low water solubility in both foods and the gastrointestinal tract, which limits the exploitation of its health-promoting properties. This study aims to formulate solid dispersions (SDs) of quercetin with hydrophilic polyethylene glycol PEG matrices, using the melt-mixing method, to improve the dissolution and antioxidant activity of quercetin. Initially, the total Gibbs free energy for different binary mixtures was modelled to predict the miscibility of the compounds. Then, the physicochemical properties of the formulated SDs were characterised and dissolution tests and antioxidant activity measurements were performed in vitro to evaluate the improved profiles and antioxidant activity of the SDs developed. The group contribution methods of Hoy and Van Krevelen and Hoftyzer, used for PEG solubility parameter calculations, presented a suitable prediction of interaction and miscibility behaviour. The results suggested the presence of amorphous quercetin precipitates in the crystalline matrix of PEG 4000 and PEG 6000, and the formation of an amorphous SD between quercetin and PEG 1000. These formulations achieved good radical scavenging activity and better dissolution, especially the quercetin-PEG 1000 SDs.

Metabolomics analysis of the effects of quercetin on Cd-induced hepatotoxicityin rats

Cadmium (Cd) is known to cause damage to the liver. In this study, metabolomics technology was used to investigate the effect of quercetin (QE) on Cd-induced hepatotoxicity. A total of 60 male SD rats were randomly divided into the following six groups: control group (C), low and high-dose QE group (Q1: 10 mg/kg·bw, Q2: 50 mg/kg·bw), Cd group (D), low and high-dose QE and Cd combined intervention group (DQ1, DQ2). The rats were given Cd chloride (CdCl2) at a concentration of 40 mg/L through free drinking water. After 12 weeks of treatment, liver samples of rats were collected for metabonlomic analysis. A total of 12 metabolites were identified, the intensities of PC (18:0/14:1(9Z)) and arachidonate acid were decreased in the Cd-treated group (p < 0.01), whereas the intensities of chenodeoxyglycocholic acid, cholic acid, taurochenodesoxycholic acid, glycocholic acid, prostaglandin D2, 15-deoxy-d-12,14-PGJ2, oxidized glutathione, cholesterol, protoporphyrin IX, bilirubin were increased significantly in the Cd-treated group compared with group C (p < 0.01). When rats were given high doses of QE and Cd at the same time, the intensity of the above metabolites was significantly restored in group DQ2. Results suggest that the protective effect of QE on Cd-induced liver injury is associated with antioxidant activity of QE, as well as QE can regulates hepatic bile acid metabolism by affecting FXR and BSEP, and regulates AA metabolism by inhibiting Cd-induced activities of COX-2 and PLA2.

Formulation, Evaluation of Physical Properties, and In Vitro Antioxidant Activity Test of Moringa Leaf (Moringa oleifera L.) Ethanolic Extract Capsules

BACKGROUND: Supplements that contain antioxidants may enhance prevention and treatment effects of a wide range of diseases including COVID-19. Quercetin, a flavonoid compound, is a natural antioxidant that can neutralize free radicals. The current study was conducted to formulate Moringa leaf (Moringa oleifera L) ethanol extract capsules and to determine the quercetin antioxidant activity levels of Moringa ethanol extract capsule formulations. &#x0D; MATERIALS AND METHODS: We tested the total flavonoid levels in solutions with concentrations of 20, 50, 60, 70 and 100 ppm using Thin Layer Chromatography Densitometric method. Evaluation of physical properties of 96% Moringa leaf ethanol extract capsules included moisture content test, granule angle of repose test, granule flow property test, capsule weight uniformity test and capsule disintegration time test. Antioxidant activity test using the DPPH method with two samples, namely 96% Moringa leaf ethanol extract capsules with formulas I, II, III, quercetin as a comparison. &#x0D; RESULT: The results of the evaluation of 96% Moringa leaf ethanol extract capsules showed that formula II (PVP 50 mg) had good physical properties. Testing the antioxidant activity of capsules of ethanol extract of Moringa leaves formulas I, II, III, quercetin obtained IC50 values of 44.0 ppm, 40.2 ppm, 46.4 ppm, and 4.80 ppm, respectively. &#x0D; CONCLUSION: The evaluation of the ethanol extract capsules of Moringa leaf formula II, met the parameters of a good capsule evaluation test requirement and had very strong antioxidant activity seen from the acquisition of the IC50 value. The antioxidant properties of Moringa leaf extract capsules may be able to improve the immune system and clinical trials need to be carried out on patients to become candidates for prevention and therapeutic supplement fora range of diseases including COVID-19.

Effects of Quercetin and Curcumin Combination on Antibacterial, Antioxidant, In Vitro Wound Healing and Migration of Human Dermal Fibroblast Cells.

Wound healing impairment due to a postponed, incomplete, or uncoordinated healing process has been a challenging clinical problem. Much research has focused on wound care, particularly on discovery of new therapeutic approaches for acute and chronic wounds. This study aims to evaluate the effect of the combination of quercetin and curcuminoids at three different ratios on the antimicrobial, antioxidant, cell migration and wound healing properties. The antioxidant activities of quercetin, curcuminoids and the mixtures were tested by DPPH and ABTS free radical scavenging assays. The disc diffusion method was performed to determine the antibacterial activities of quercetin, curcuminoids and the mixtures against S. aureus and P. aeruginosa. The cytotoxicity and cell migratory enhancing effects of quercetin, curcuminoids and the mixtures against human dermal fibroblasts were investigated by MTT assay, scratch assay and Transwell migration assay, respectively. The results showed the synergism of the quercetin and curcuminoid combination to inhibit the growth of S. aureus and P. aeruginosa, with the inhibition zone ranging from 7.06 ± 0.25 to 8.78 ± 0.38 mm, respectively. The DPPH free radical scavenging assay demonstrated that the combination of quercetin and curcuminoids yielded lower IC50 values (15.38–23.70 µg/mL) than curcuminoids alone (25.75 µg/mL). Quercetin and a 3:1 quercetin/curcuminoid mixture at non-toxic concentrations showed the ability to stimulate the migration of fibroblasts across the matrix, whereas only quercetin alone accelerated the wound closure of fibroblasts. In conclusion, the mixture of quercetin and curcuminoids at a 3:1 ratio was the best formulations for use in wound healing due to the antimicrobial, antioxidant and cell-migration-enhancing activities.

Study on Antioxidant Activity of Quercetin from Seabuckthorn Meal in Vitro and Its Protective Effect on Aging Mice

The antioxidant activity and protective effect of quercetin from seabuckthorn meal were studied in vitro. The antioxidant activities of quercetin in seabuckthorn were studied by 1, 1-diphenyl-2-trinitrophenylhydrazine (DPPH·) superoxide anion ( \begin{document}${\rm{O}}_2^- \cdot $\end{document} ), 2, 2-diazo-bis (3-ethyl-benzothiazole-6-sulfonic acid) diammonium salt (ABTS+·) and high iron ion reduction (FRAP). The aging model of mice was established by subcutaneous injection of D-galactose into the neck. The mice were treated with quercetin of seabuckthorn meal at different doses (100, 250, 500 mg/kg) by gavage. The eyeball blood was taken to measure the activities of total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and malondialdehyde (MDA) in serum; the heart, kidney and liver were taken as hematoxylin eosin staining (HE) to observe the pathological state of the cells. The results showed that quercetin from seabuckthorn meal had good scavenging ability on DPPH·, \begin{document}${\rm{O}}_2^- \cdot $\end{document} and ABTS+·. Compared with the model group, the content of MDA in the low dose group of quercetin of seabuckthorn meal decreased significantly (P<0.05), the activities of T-AOC, GSH-Px and SOD in the serum of mice in the medium and high dose groups increased significantly (P<0.05), and the content of MDA decreased significantly (P<0.05). From the pathological section, with the increase of quercetin dosage in seabuckthorn meal, the myocardial fibers arranged orderly and the transverse lines were clear; the morphology of renal sacs and glomeruli gradually became normal, the number of renal tubules increased and arranged closely; the number of hepatocytes increased, the cell morphology was complete, and the sinus space gradually became significant. Therefore, quercetin from seabuckthorn meal could improve the activity of antioxidant enzymes and the content of reducing substances in aging model mice, reduce the content of lipid peroxide, so as to improve the antioxidant capacity of aging model mice, and had a better protective effect on aging model mice.

Antioxidant activity and controlled‐release feature of Quercetin loaded amines‐functionalized magnetically porous cellulose

AbstractLoading of quercetin onto drug cargo is still progressively studied to not only improve its solubility but also control the release behavior for improving therapeutics efficacy. In this present study, we successfully prepared drug cargo based magnetically porous cellulose (PC) functionalized by amine‐based alkoxysilane (MPC−NH2) for effectively carrying and sustainably delivering quercetin. The PC derived from oil palm empty fruit bunches provides high loading capacity reaching 344.48 ± 5.69 mg/g with loading effectiveness of 67.02 ± 1.11%. Surface modification of PC surfaces by Fe3O4 nanoparticles and aminosilane compounds not only enhances the quercetin loading effectiveness to 80.83 ± 1.10% but also controls the quercetin release behavior either at artificial gastric or physiological condition. The kinetic release study elaborates that anomalous transport is mainly involved during release of quercetin under physiological condition, but the Fickian diffusion plays the role at artificial gastric condition. The kinetic release rate of quercetin calculated following Higuchi model indicates that the Que@MPC−NH2 has slower release rate compared to another drug carrier. Additionally, the antioxidant activity of quercetin is significantly improved after being loaded onto MPC−NH2. Finally, we recapitulate that the loading of quercetin within MPC−NH2 is a powerful strategy for improving loading capacity, drug‐release ability, and antioxidant activity.